The present invention relates to a new and improved construction of apparatus for applying solder to printed circuit boards.
Generally speaking, the solder application apparatus of the present development is of the type comprising a solder bath into which there are immersed the printed circuit boards in essentially vertical direction.
It is known to the art to subject printed circuit boards containing a conductive path or pattern formed of bear copper to a hot tin-plating process, wherein by immersing the printed circuit boards into a tin bath the molten solder (a lead-tin alloy, normally the eutectic alloy tin-lead 63/37) directly acts upon the copper. After a certain period of time the printed circuit boards are withdrawn out of the hot tin bath and brought out of their vertical position into a horizontal position, where the solder can soldify. Since the carrier material of the printed circuit board, for instance an epoxy resin, is heated within the solder bath up to its softening temperature, the printed circuit board is extremely soft after departing from the solder bath. Therefore, the printed circuit board, during the transfer from the vertical into the horizontal position, tends to deform.